This paper assesses the extent to which the new public management (NPM) project has succeeded in replacing the custodial mode of professional work supervision with a more bureaucratic approach. The paper conceptualizes the key components of each mode within two ideal types of professional work supervision. It then draws on findings from a study of local‐authority social service departments to consider current arrangements against these ideal type configurations. The findings demonstrate that elements of the bureaucratic mode have emerged unevenly. So far, they have not displaced the emphasis that the supervisors of professional work place on protecting autonomy and limiting management control systems. This suggests that custodial approaches to the supervision of professional work may be more resilient than has been assumed within previous analyses of NPM.